Bright squeezed vacuum: bunching and superbunching

31.10.2012, 14:28

Newsletter 5

Phys Rev Lett ront page, Vol 109 issue 15

Recently we have produced bright non-classical states of light, manifesting the effects of photon bunching and super-bunching. Such states are of extreme interest in nonlinear optics. In the experiment these states are generated by single-mode selection of the bright squeezed vacuum produced by high-gain parametric down conversion. A single mode of down-converted radiation demonstrates photon bunching in the frequency-non-degenerate collinear regime, whereas in the frequency-degenerate collinear regime super-bunching is seen. The probability distributions for bunching and super-bunching are clearly distinguishable. The dashed curves are theoretical fits. Despite strong filtering the states remain macroscopic, containing on average 8000 photons per pulse. The number of modes in the prepared states was estimated from a measurement of the second-order intensity correlation function g(2). The measured values of g(2) were 1.8 (bunched) and 2.6 (super-bunched). Assuming that g(2) = 2 for the bunched and 3 for the super-bunched state, the effective number of modes is 1.25.